Fiber treatment agent composition

ABSTRACT

A fiber treatment agent composition comprising an amphipathic lipid having hydroxyl group(s) and amide group(s) in the molecule thereof, the lipid being solid particles having an average particle size of 1 to 100 μm. The fiber treated with the fiber treatment agent composition of the invention provides excellent feeling to the resultant textile and pleasant feel to the skin. When a consumer wears the fiber product produced from the thus-treated fiber, remarkable effects are attained, including pleasant feel to the skin with which the fiber product is brought into contact, skin protective effect, effect of enabling the people having sensitive skin to wear at ease, moisturizing effect, and effect of improving skin disease such as rough skin.

TECHNICAL FIELD

The present invention relates to a fiber treatment agent compositionimparting excellent feeling to fibers, and to a fiber which providesexcellent sense of touch and excellent feel when a consumer wears an endproduct produced from the fiber. More particularly, the inventionrelates to a fiber treatment agent composition containing an amphipathiclipid in solid particulate form having a specific average particle sizethat is beneficial for treatment of fiber; to a fiber bearing theamphipathic lipid on a surface thereof; and to a method of treating thefiber.

BACKGROUND ART

In recent years, treated fibers designed to produce effects analogous tothose of skincare cosmetics have found utility in textile products,particularly those worn by consumers in their everyday lives. JapanesePatent Application Laid-Open (kokai) No. 8-60547 discloses a skincarefiber product to which serine-containing protein is attached. JapanesePatent Application Laid-Open (kokai) No. 2001-146680 discloses afinishing composition for textiles containing a nonionic amphipathicsubstance. More specifically, the nonionic amphipathic substance is aceramide, and preferably, the ceramide is present, along with othercomponents, in the composition while in the form of emulsion particleshaving a particle size of not more than 1,000 nm. By virtue of thesefeatures, the composition disclosed therein is reported to exhibitexcellent emulsion stability over time, preventing precipitation ofceramides, and excellent cohesion or adhesion of ceramides to fibers tobe treated. Also, the treated textile products promotemoisture-retaining ability of the skin when consumers wear the products.Thus, the ceramides disclosed in this publication are not present insolid form.

However, these techniques are not necessarily satisfactory, in thatceramides cannot be retained on the fiber in such amounts that canprovide sufficient effects, laundry durability is low, and feeling ofthe fiber cannot be improved without sacrificing other features.

An object of the present invention is to provide a fiber treatment agentcomposition which is capable of causing an amphipathic lipid havingskincare effect to be stably retained on the fiber; which impartsexcellent feeling to the fiber; and which, when a consumer wears an endproduct producing from the fiber, exhibits moisturizing effect to theskin and imparts pleasant feel to the skin with which the fiber productcomes into contact.

DISCLOSURE OF THE INVENTION

The present invention provides a fiber treatment agent compositioncomprising an amphipathic lipid having hydroxyl group(s) and amidegroup(s) in the molecule thereof, said lipid being solid particleshaving an average particle size of 1 to 100 μm.

The present invention also provides a fiber treatment agent compositionfurther comprising, in addition to the above-mentioned fiber treatmentagent compositions one or more species selected from the groupconsisting of surfactants and aqueous medium.

The present invention also provides a treated fiber which is obtainedthrough bringing the above-mentioned fiber treatment agent compositioninto contact with fiber so that the above-mentioned amphipathic lipid iscaused to be present continuously or discontinuously on a surface of thefiber.

The present invention also provides a fiber to which the above-mentionedamphipathic lipid has been affixed.

The present invention also provides a method of treating fibercomprising bringing the above-mentioned fiber treatment agentcomposition into contact with fiber.

BEST MODE FOR CARRYING OUT THE INVENTION

As used herein, the “amphipathic lipid having hydroxyl group(s) andamide group(s) in the molecule thereof” (hereinafter, may be referred toas component (a)) is defined as such a lipid that contains one or morehydroxyl groups and one or more amide groups in the molecule of thelipid; that falls within the class consisting of natural ceramides,synthetic ceramides, and analogs (pseudo-ceramides) prepared therefromthrough, for example, synthesis; and that is solid at room temperature(25° C.) Examples of the amphipathic lipid include Ceramide H03(Sederma), CeramideII (Sederma), Quesamide H (Quest), Ceramide TIC-001(Takasago International Corporation), and SOFCARECERAMIDE SL-E (KaoCorporation). From the viewpoint of stability of the lipid incorporatedin the fiber treatment agent composition, the lipid preferably has amelting point of not less than 30° C., more preferably not less than 40°C. Among synthesized ceramide analogs, particularly preferred ones areamide derivatives represented by the following formula (1) (includingthe above-mentioned SOFCARECERAMIDE SL-E:

wherein R¹ and R² are the same or different and each independentlyrepresents a linear or branched, saturated or unsaturated C₇-C₃₉hydrocarbon group which may be substituted by one or more hydroxylgroups; and R³ and R⁴ are the same or different and each independentlyrepresents a hydrogen atom, a phosphate salt residue, a sulfate saltresidue, or a saccharide residue; provided that one or more hydroxylgroups are contained in one molecule of the derivative.

In the formula (1), R¹ is preferably a linear or branched, saturated orunsaturated C₉-C₂₅ hydrocarbon group; R² is preferably a linear orbranched, saturated or unsaturated C₁₀-C₂₆ hydrocarbon group; and eachof R³ and R⁴ is preferably a hydrogen atom.

Methods for producing the above-mentioned amide derivative (1) aredescribed in detail in, for example, Japanese Patent ApplicationLaid-Open (kokai) No. 62-228048 and No. 63-216852.

The amphipathic lipid is solid particles having an average particle sizeof 1 to 100 μm, preferably 2 to 100 μm, more preferably 5 to 100 μm,even more preferably 5 to 80 μm, most preferably 7 to 50 μm. Preferably,the solid particles are present in a crystalline state.

The above-mentioned amphipathic lipids, which may be employed alone orin combination of two or more species, are incorporated in the fibertreatment agent composition of the present invention in an amount of0.005 to 40 wt. %, preferably 0.05 to 40 wt. %, more preferably 5 to 40wt. %, most preferably 10 to 30 wt. %. When the fiber treatment agentcomposition is a thick solution, the amount of the amphipathic lipids inthe fiber treatment agent composition is preferably 1 to 40 wt. %, morepreferably 5 to 40 wt. %, most preferably 10 to 30 wt. %, whereas whenthe composition is a dilute solution, their amount in the fibertreatment agent composition is preferably 0.005 to 1 wt. %, morepreferably 0.01 to 0.9 wt. %, most preferably 0.02 to 0.6 wt. %.

No particular limitations are imposed on the surfactant (hereinafter maybe referred to as component (b)) which may be used for the preparationof the fiber treatment agent composition of the present invention, andone or more species of surfactants may be suitably selected fromnonionic surfactants, anionic surfactants, amphoteric surfactants, andcationic surfactants.

In the case where the amphipathic lipid is first subjected tocrystallization along with component (b) and then incorporated into thefiber treatment agent composition, the component (b) is preferably oneor more species selected from those ordinarily employed for cosmeticuse; for example, selected from nonionic surfactants, anionicsurfactants, and amphoteric surfactants.

Examples of the nonionic surfactants include alkyl polyglycosides,polyoxyalkylene alkyl or alkenyl ethers, polyoxyalkylene sorbitan fattyacid esters, sorbitan fatty acid esters, polyoxyalkylene sorbitol fattyacid esters, polyoxyalkylene glycerin fatty acid esters, polyglycerinfatty acid esters, fatty acid monoglycerides, polyethylene glycol fattyacid esters, and fatty acid alkanol amides.

Examples of the anionic surfactants include polyoxyalkylene alkyl etheracetic acid or salts thereof, N-acylamino acid salts, polyoxyalkylenealkyl ether sulfate salts, polyoxyalkylene alkyl ether phosphate salts,alkylphosphate salts, N-acylmethyltaurine salts, alkylsulfosuccinatesalts, polyoxyalkylene alkylsulfosuccinate salts, and fatty acid salts.

Examples of the amphoteric surfactants include alkylaminoacetatebetaine, alkylamine oxide, alkylamide propyl betaine, alkylhydroxysulfobetaine, and amido amino acid (imidazoline-type betaine).

Preferred surfactants are nonionic surfactants and polyoxyethylene alkylether acetic acid or salts thereof. Preferred nonionic surfactants arealkyl polyglycosides, polyoxyalkylene alkyl or alkenyl ethers,polyoxyalkylene sorbitan fatty acid esters, and sorbitan fatty acidesters.

Most preferred nonionic surfactants include alkyl polyglycosides (e.g.,those in which the alkyl group has 8 to 14 carbon atoms and a glucosecondensation degree is 1 to 2), polyoxyalkylene alkyl or alkenyl ethers(e.g., those in which the alkyl or alkenyl group has 8 to 18 carbonatoms and the average mol number of added ethylene oxide is 4 to 25,preferably 4 to 15), polyoxyalkylene sorbitan fatty acid esters (e.g.,those in which the fatty acid has 8 to 20 carbon atoms and the averagemol number of added ethylene oxide is 5 to 25), and sorbitan fatty acidesters (e.g., monoesters of fatty acid having 8 to 20 carbon atoms).

Examples of the polyoxyalkylene alkyl ether acetic acid or salts thereofinclude such acids per se having 8 to 20 carbon atoms and an average molnumber of added ethylene oxide of 3 to 15; and alkali metal saltsthereof. That is, the polyoxyalkylene alkyl ether acetic acid may beused as is (without neutralization) or after being neutralized.

When a cationic surfactant is further added, enhanced adsorption of theamphipathic lipid onto the fiber can be attained. Examples of thecationic surfactants include mono(long-chain alkyl)ammonium salts,di(long-chain alkyl)ammonium salts, benzalkonium salts, benzethoniumsalts, and pyridinium salts.

Any of the above-mentioned surfactants may be employed singly or incombination of two or more species. The surfactant(s) may beincorporated in the fiber treatment agent composition in an amount of 2to 55 wt. %, preferably 5 to 40 wt. %. When a crystallization step isperformed, it is particularly preferred that these ranges be met.

The ratio by weight of amphipathic lipid to surfactant; i.e., (a)/(b),is preferably 90/10 to 25/75, more preferably 80/20 to 30/70, mostpreferably 70/30 to 40/60. When a crystallization step is performed, itis particularly preferred that these ranges be met.

As used herein, the aqueous medium which may be employed for producingthe fiber treatment agent composition of the present invention is waterand/or a polar organic solvent which is soluble in water. Examples ofwater-soluble polar organic solvents include alcohols such as methanol,ethanol, and propanol; glycols such as ethylene glycol, propyleneglycol, diethylene glycol, and polyethylene glycol; and acetone.

Preferred examples of the aqueous medium include water, ethanol, andglycols, with water being most preferred.

In treatment of fiber, the fiber treatment agent composition of thepresent invention may be used as is or after diluted with water and/or awater-soluble polar organic solvent, or alternatively diluted with asurfactant and an aqueous medium. When the fiber treatment agentcomposition of the present invention is a thick solution, thecomposition is preferably diluted before use.

The fiber treatment agent composition of the present invention can beproduced by, for example, heating a mixture of an amphipathic lipid(component (a)), a surfactant (component (b)), and water to atemperature of not less than the melting point of the amphipathic lipid(from the melting point to about a temperature 10° C. higher than themelting point) under stirring, to thereby melt the mixture, and afterthe melt became a homogeneous state, cooling the melt under stirring, soas to cause crystallization of the component (a).

In this process, the particle size of component (a) can be regulatedthrough control of the type and amount of the surfactant, cooling rate,and speed of stirring or the like. Preferably, component (a) has anaverage particle size of 1 to 100 μm, more preferably 2 to 100 μm, stillmore preferably 5 to 100 μm, even more preferably 5 to 80 μm, mostpreferably 7 to 50 μm, as measured by the method described hereinbelow.As used herein, the average particle size is an arithmetic mean valuedetermined by photographing the particles under an optical microscopeunder transmission light, selecting arbitrary 30 particles on aphotograph, and for each of the 30 particles, measuring the major axisof the particle.

The fiber treatment agent composition of the present invention may alsocontain a pH-regulator, a preservative, a softening agent, a hardeningagent, an antistatic agent, an antimicrobial/deodorizing agent, amoisturizing agent and so on.

Examples of the moisturizing agent include plant extracts, sodiumhyaluronate, collagen, animal oils, vegetable oils, paraffin, liquidparaffin, vaseline, ceresine, squalane and so on.

Plant extracts are extracts obtained through any of a variety of plants,and examples thereof include aloe, aloe vera, ginkgo, fennel, seaweed,pueraria root, chamomile, kiwi, cucumber, dishcloth gourd, gardenia,rice bran, peach, citron, adlay, mugwort, Saint-John's-wort, tea and soon.

Examples of vegetable oils include olive oil, camellia oil, macadamianut oil, castor oil, carnauba wax, candelilla wax, jojoba oil, saffloweroil, soybean oil, shea oil, sunflower oil, cacao oil, coconut oil, palmkernel oil, meadowfoam seed oil, rice germ oil, orange oil and so on.

Examples of animal oils include mink oil, beeswax, lanolin and so on.

Examples of fibers used in the present invention include natural fiberssuch as cotton, silk, hemp, and wool; regenerated fibers such as rayon,cuprammonium rayon, and tensel; semi-synthetic fibers such as acetate,diacetate, and triacetate; and synthetic fibers such as polyester,nylon, acrylic, vinylon, polypropylene, and polyurethane. No particularlimitations are imposed on the form of the fiber, and examples of thefiber include a variety of fibrous materials such as staple fiber andyarn; semi-products such as nonwoven fabric, knit fabric, and wovenfabric; and end products such as clothes and bedclothes.

Preferred examples of fiber products produced from the above-mentionedfibers include those which are used in direct contact with skin or hair;specifically, underwear such as panty hoses, tights, lingerie,petticoats, camisoles, shorts, undershirts, trunks, and briefs;foundations such as girdles, brassieres, and body suits; night wearssuch as night dresses, pajamas, and bathrobes; clothes such as leotards,socks, stomach bands, gloves, mufflers, masks, towels, and headgears;and bedclothes such as pillow covers and sheets.

According to one method of the present invention for treating fiber,fiber is brought into contact with the fiber treatment agent compositionof the present invention.

Such a step of bringing fiber into contact with the fiber treatmentagent composition may include immersion of fiber in the fiber treatmentagent composition, followed by drying; and spraying the fiber treatmentagent composition onto fiber, followed by drying. Such treatment yieldsfibers bearing the amphipatic lipid in a continuous fashion ordiscontinuous fashion oh a surface of the fiber. Drying may be performedthrough either naturally or with application of heat. Pressurized heattreatment may be performed by use of, for example, an iron or trouserspresser.

Examples of specific treatment method include the pad drying methodusing a mangle and a dryer; the dip dyeing method employing a wincedyeing machine, a cheese dyeing machine, or a jet dyeing machine; thespray method; the coating method; the printing method; and the additiveblending method applied for rayon or acrylic fibers.

When textile products are concerned, the fiber treatment agentcomposition of the present invention may be used in any step duringlaundry, e.g., in a washing step, a rinsing step, a softener-finishingstep, or a sizing step. Alternatively, the fiber treatment agentcomposition of the present invention may be directly applied to clothingor bedclothes by the spray method and so on.

In the fiber treatment method of the present invention, the amphipathiclipid is preferably employed in an amount of 0.001 to 5 wt. %, morepreferably 0.05 to 1 wt. %, most preferably 0.1 to 0.8 wt. %, withrespect to the weight of the fiber.

In treating the fiber, a binder may optionally be used. Use of a binderis preferred from the viewpoint of laundry durability. Examples of thebinder include silicone resins, acrylic resins, urethane resins, vinylacetate resins and so on. In this case (i.e., when treatment of fiber isperformed), in addition to a binder, there may also be used thefollowing agents depending on purposes: softening agent, hardeningagents, sewing facilitating agents, flame retardants, antistatic agents,soil repellents, antimicrobial/deodorizing agents, raising agents,slip-preventing agents, moisturizing agents, water repellants, waterabsorbers, fluorescent dyes, anti-shrinking agents such as glyoxal,fixing agents and so on.

From the viewpoints of good laundry durability and fiber treatmenteffect, the binder is preferably employed in an amount of 10 to 500 wt.%, more preferably 50 to 300 wt. %, with respect to the weight of theamphipathic lipid, wherein the calculation is on the basis of solidcomponents of the binder.

It is believed that, the amphipathic lipid of the invention, due to itsspecific form (i.e., solid particles having an average particle size of1 to 100 μm), does not tend to be incorporated into the inside of thetreated fiber, but is effectively affixed onto the surface of fiber ascompared with amphipathic lipids in solubilized form or emulsified form.Moreover, when the fiber treatment process includes a washing step orrinsing step, amphipathic lipids in solubilized form or emulsified formare easily removed through washing. According to the present invention,however, since the amphipathic lipid is solid particles having anappropriate size, it is not easily washed away, whereby attainingimproved retention of the lipid in fiber. From these reasons, fiber thathas undergone treatment with the fiber treatment agent composition ofthe invention is considered to exhibit excellent feeling of theresulting textile and pleasant feel to the skin.

EXAMPLES Example Nos. 1 through 3 and Comparative Example 1 Preparationof Fiber Treatment Agent Composition

The amphipathic lipids, surfactants, and water shown in Table 1, incolumns of Example Nos. 1 through 3 were heated to 80 to 90° C.Subsequently, each of the resultant mixtures was cooled under stirring,to thereby allow the amphipathic lipid to crystallize. Stirring wasfurther performed and the mixture was cooled to room temperature, tothereby yield a fiber treatment agent composition. The amphipathic lipidcontained in the resultant composition was found to be solid particlesof needle-like to plate-like crystals having an average particle size of11.8 μm (Example 1), 8.9 μm (Example 2), or 16.3 μm (Example 3). Thecrystalline state was confirmed through X-ray diffraction.

In Comparative Example 1, the procedure of Example 1 was repeated,except that the 32.0 parts by weight of MYDOL 10 was replaced by 23.0parts by weight of RHEODOL TW-S120, to thereby obtain a composition inwhich the amphipathic lipid remains uncrystallized but is present asemulsion particles (confirmed through X-ray diffraction). TABLE 1 (partsby weight) Comp. Exam- Examples ple 1 2 3 1 (a) Formula (1) 20.0 23.015.0 20.0 Amphipathic R¹ = C₁₅H₃₁ lipid R² = C₁₆H₃₃ R³ = H R⁴ = H (m.p.:74-76° C.) Formula (1) 3.0 R¹ = C₁₇H₃₅ R² = C₁₄H₂₉ R³ = H R⁴ = H (m.p.:78-80° C.) (b) MYDOL 10*¹ 32.0 25.0 Surfactant EMULGEN 106*² 15.5 KAOAKYPO 2.0 RLM-100*³ RHEODOL 23.0 TW-S120*⁴ Water balance balance balancebalance Average particle size (μm) 11.8 8.9 16.3 1 or less Particle formSolid Solid Solid Liquid particles particles particles particles*¹Kao, Decyl polyglycoside (Condensation degree: 1-1.35), Effectiveingredient: 40 wt. %*²Kao, Polyoxyethylene (5) lauryl ether*³Kao, Polyoxyethylene (10) lauryl ether acetic acid, Effectiveingredient: 89 wt. %*⁴Kao, Polyoxyethylene (20) sorbitan monostearate

Test Example 1 and Comparative Test Examples 1 and 2

1 g of the fiber treatment agent composition obtained from Example 1 wasdispersed in 2.0 L of water, and 25 g of a pair of panty hose, which hadbeen washed five times with a commercially obtained detergent, wassoaked therein. Subsequently, the panty hose were dewatered once, thenrinsed in an equivolume of water, followed by dewatering again, naturaldrying, to thereby obtain a treated fiber product of the presentinvention. In the same manner, three pairs of panty hose were prepared,and were provided to a panelist. Then five women panelists, who have dryskin and often complain itchiness when they wear panty hose, carried outwearing test of the panty hose for 3 days in winter (Test 1).

For comparison, by use of the composition obtained from ComparativeExample 1; i.e., the composition in which the amphipathic lipid remainsuncrystallized but is present as emulsion particles, several pairs ofpanty hose were treated in a similar manner, and wearing test wascarried out by the same five panelists as in Test Example 1 (ComparativeTest 1). Also, wearing test of several pairs of panty hose that haveundergone similar treatment, but undergone no treatment with fibertreatment agent composition, was carried out (Comparative Test 2).

The results are all shown in Table 2. The evaluation items andevaluation criteria are as follows. The results shown in the Table areaverage ratings from the 5 panelists.

Feeling of Fabric (Feel to Touch)

-   -   4: Very good    -   3: Good    -   2: Slightly poor    -   1: Poor        Ease of Wearing (Smoothness)    -   4: Very good    -   3: Good    -   2: Slightly poor    -   1: Poor        Change in Sensation Felt by the Skin by Wearing    -   4: Turned very good    -   3: Turned better    -   2: No change    -   1: Turned worse        Moisturizing Effect by Wearing    -   4: Very effective    -   3: Effective    -   2: Somewhat effective    -   1: Not effective        Itchiness of the Skin After Wearing    -   4: Itchiness was removed    -   3: Itchiness was removed to some extent    -   2: No change

1: Itchiness aggravated TABLE 2 Test 1 Comp. Test 1 Comp. Test 2 Feelingof fabric 3.6 1.8 1.6 Ease of wearing 4.0 2.2 2.0 Change in sensation3.8 2.2 1.8 felt by the skin Moisturizing effect 3.4 1.2 1.0 Itchinessof the skin 3.4 2.2 1.8

As is apparent from Table 2, the fiber which has been treated with thefiber treatment agent composition of the present invention impartsexcellent feeling to the resultant fiber product, exhibits smoothness ofthe fiber product when a person wears the same, improves touch to theskin, enhance the moisturizing effect, and mitigates itchiness of theskin.

Test Example Nos. 2 through 4

Each 5 g of the fiber treatment agent compositions obtained fromExamples 1, 2, and 3 (corresponding to Tests 2, 3, and 4, respectively)was dispersed in 10.0 L of water. 1.0 Kg of cotton fiber (cotton fabric)was soaked in the resultant dispersion. Thereafter, the cotton fiber wassqueezed with a mangle, then dried at 55° C. for 30 minutes, to therebyyield a treated fiber of the present invention.

Ten panelists consisting of five men and five women touched the treatedfiber and fiber that had undergone a similar treatment without use ofthe fiber treatment agent composition of the present invention, tocompare them in terms of sensation by the blind method. The results areshown in Table 3. The evaluation criteria are shown below. The ratingsshown in Table 3 are average values of the ratings given by the 10panelists.

Sensation

-   -   5: The invention product is much better    -   4: The invention product is better    -   3: Comparable    -   2: Non-treated product is better

1: Non-treated product is much better TABLE 3 Test 2 Test 3 Test 4Sensation 4.4 4.1 3.8

As is apparent from Table 3, as compared with the fiber products thathad undergone no treatment, those treated with the fiber treatment agentcomposition of the present invention provide excellent sensation totouch by hands.

Example 4

The fiber treatment agent composition of the present invention can beincorporated in a softening agent composition and can be used forimparting softness to fiber products. Fiber treatment agent composition(Ex. 1)  10.0% QUARTAMIN D86P*¹⁾  3.0% EMULGEN 123P*²⁾  0.5% Ethyleneglycol  1.5% Water balance Total 100.0%*¹⁾Distearyl dimethyl ammonium chloride (product of Kao Corporation,effective ingredient 75%)*²⁾Polyoxyethylene (23) lauryl ether (product of Kao Corporation)

Example 5

Fiber treatment agent composition (Ex. 2)  2.5% Perfume q.s. Waterbalance Total 100.0%

The resultant composition is placed in a spray container, followed byshaking well, and spraying onto fiber products uniformly.

Industrial Applicability

The fiber treated with the fiber treatment agent composition of thepresent invention provides excellent feeling to the resultant textileand pleasant feel to the skin. When a consumer wears the fiber productproduced from the thus-treated fiber, remarkable effects are attained,including pleasant feel to the skin with which the fiber product isbrought into contact, skin protective effect, effect of enabling thepeople having sensitive skin to wear at ease, moisturizing effect, andeffect of improving skin disease such as rough skin.

1. A fiber treatment agent composition comprising an amphipathic lipidhaving hydroxyl group(s) and amide group(s) in the molecule thereof,said lipid being solid particles having an average particle size of 1 to100 μm.
 2. The fiber treatment agent composition as claimed in claim 1,wherein the amphipathic lipid is obtained through heating a mixture ofthe amphipathic lipid, a surfactant, and/or an aqueous medium to atemperature not less than the melting point of the amphipathic lipid,and a subsequent crystallization step.
 3. The fiber treatment agentcomposition as claimed in claim 1 or 2, wherein the amphipathic lipid isrepresented by the following formula (1):

wherein R¹ and R² are the same or different and each independentlyrepresents a linear or branched, saturated or unsaturated C₇-C₃₉hydrocarbon group which may be substituted by one or more hydroxylgroups; and R³ and R⁴ are the same or different and each independentlyrepresents a hydrogen atom, a phosphate salt residue, a sulfate saltresidue, or a saccharide residue; provided that one or more hydroxylgroups are contained in one molecule of the derivative.
 4. The fibertreatment agent composition as claimed in any one of claims 1 through 3,wherein the amphipathic lipid is contained in an amount of 0.005 to 40%by weight of the fiber treatment agent composition.
 5. The fibertreatment agent composition as claimed in any one of claims 1 through 4,further comprising one or more species selected from the groupsconsisting of surfactants and aqueous medium.
 6. A treated fiberobtained through bringing a fiber treatment agent composition as recitedin any one of claims 1 through 5 into contact with fiber so as to causethe amphipathic lipid to be present continuously or discontinuously onthe surface of the fiber.
 7. A fiber to which an amphipathic lipid hasbeen affixed, the amphipathic lipid having hydroxyl group(s) and amidegroup(s) in the molecule thereof and being solid particles having anaverage particle size of 1 to 100 μm.
 8. A method of treating fiber,comprising bringing the fiber treatment agent composition as recited inany one of claims 1 through 5 into contact with fiber.
 9. The method oftreating fiber according to claim 8, wherein the fiber is treatedthrough dipping in the fiber treatment agent composition.
 10. The methodof treating fiber according to claim 8, wherein the fiber is treatedthrough spraying of the fiber treatment agent composition to the fiber.11. The method of treating fiber according to any one of claims 8through 10, wherein, when the fiber is brought into contact with thefiber treatment agent composition, at least one species selected fromthe following group is co-used: binders, softening agents, hardeningagents, sewing facilitating agents, flame retardants, antistatic agents,soil repellents, antimicrobial/deodorizing agents, raising agents,slip-preventing agents, moisturizing agents, water repellants, waterabsorbers, fluorescent dyes, anti-shrinking agents, and fixing agents.12. Use, in a fiber treatment agent composition, of an amphipathic lipidhaving hydroxyl group(s) and amide group(s) in the molecule of the lipidand being solid particles having an average particle size of 1 to 100μm.